Liquids are dispensed from liquid containers in a variety of means, depending upon the physical properties of the liquid being poured and on the ease and/or accuracy of dispensing being sought. The dispensing means ranges from the ubiquitous mustard dispenser or liquid dishwashing detergent dispenser to those used in the laboratory dispensing hazardous chemicals of an ultrapure nature. Amounts dispensed vary from single droplets to a steady stream. Their complexity varies from the plastic caps seen on household goods to mechanical pumps found in laboratories, which are devices that are typically based upon some form of piston and valve assembly. How well they dispense is in the eye of the consumer, be it the tolerance for the smear of excess material on the cap associated with a squeeze mustard or dishwashing soap container, to the precise demands of the analytical chemist who may worry about any wayward droplets of hazardous materials or contamination by foreign material. Also of importance is the ease with which the cap can be removed to allow cleaning and subsequent disposal. In the present invention, liquids can be easily dispensed in a drop-like or stream-like manner, while also being neatly and safely contained within the environs of the spout in a noncontaminating fashion. The present invention is also easily unscrewed, facilitating cleanup and disposal.
The current modes of dispensing liquids from containers vary from simply pouring—which is inaccurate and gross volumetrically—to elaborate mechanical dispensers based upon a calibrated piston and check valves—which dispense accurately, but invariably contaminate the product through the particles produced by wear. In between these extremes lies a variety of ‘drop’ dispensing style of caps such as those shown in FIG. 1.
The Yorker Spout Cap (FIG. 1A) is one of the simplest devices, typically seen on ketchup or mustard containers and in glue dispensers. The straight taper of the spout allows a ready stream of liquid to be squeezed out, making it ideal for viscous liquids like ketchup and mustard. The tapered spout allows some drawback of the liquid from the zone near the orifice, but can leave significant globules in the orifice itself or in the immediate vicinity, depending upon viscosity of the liquid. The common result is dribbling and spurting of material held up in the spout area. The small, snap-on cap exacerbates the smear.
The Snap-Top Cap (FIG. 1B), in contrast, has a very short (typically 2-4 mm) pour spout. This short spout tends to promote dribbling and smearing, particularly for viscous or runny fluids. Flaring or shaping the spout reduces, but does not eliminate, the dribbling. The height of this pour spout is limited by the geometry of the hinged lid. The sealing plug approaches at an angle to the orifice, requiring looser tolerances, which in turn promotes leakage and smearing of the contents over the cap. A lack of mechanical advantage in effecting the closure aggravates the leakage. This type of cap is often seen on household cleaners and shampoo bottles.
The common Eye Dropper cap (FIG. 1C) has an extended pour spout with a rounded end. The latter helps avoid damage to the eye. However, the rounded shape of the tip also promotes dribbling or smearing of the liquid being dispensed—this is desirable for coverage over the cornea, but not for clean and precise dispensing of droplets.
The Stull Twist Cap (FIG. 1D) and the Pull & Push Cap (FIG. 1E) both have a central shaft and a captive, outer cap which combine together to effect a seal. The gap between the shaft and the outer cap tends to trap material. Material left behind on the tip of the central shaft leads to smearing of the contents, or forms an undesirable, dried residue. The Stull Twist cap has a more sharply defined tip, allowing droplets to be formed in a more discrete manner than the rounded version in the Pull & Push cap. However, both types of cap tend to leak or smear material as the cap used to seal the orifice is pushed or rotated downwards. The Stull Twist cap is usually seen on mustard/ketchup bottles; the Pull & Push cap, on liquid dish soap containers.
The Flip-Up Spout (FIG. 1F) and the Disc Top cap (FIG. 1G) have similarly hinged pour spouts. The gaps around these spouts tend to accumulate excess material and thereby trap contaminants. The straight, unoccluded bores of these spouts are limited both in the fineness and in the control of the droplets dispensed. The blunt or squared off ends of the pour spouts also tend to encourage dribbling. This type of cap is often seen on shampoo bottles.
The ‘JT Baker’ dropper cap (FIG. 1H) is used exclusively by JT Baker Co and its distributors for laboratory solutions and acids. It uses a snap-in cap for attachment to the bottle. It has a well-formed nozzle with a relatively small flare to the pour spout. A hanging basket type of baffle with rectangular holes extends inwards. Also, the sizing of the nozzle and the nature of the baffle encourage the dispensing of two or more discrete droplets, rather than single ones in less viscous liquids. The JT Baker Cap has no antechamber that acts via surface tension to draw back liquid entrained in the nozzle. Relatively large openings, which encourages the dispensing of larger volumes or multiple droplets, are used in the baffle to allow liquid to drain back, rather than the pull exerted by liquid in an antechamber as in the present invention. The snap-in cap can be easily damaged during installation, causing leakage. The snap-in cap also creates a handling and environmental problem in rinsing the residual container contents when the empty container is disposed of. Finally, the snap-in cap can occlude foreign material, possibly contaminating the product.
The ‘Merck’ dropper cap (FIG. 1I) is used by Merck KGaA and its subsidiaries for laboratory solutions and acids. This snap-in type of cap has a nozzle with a straight bore and a blunt tip, which allows liquid to dribble down the spout. The unobstructed spout has a separate vent and drip control extension on the inside. No baffling is in place to prevent any spit back of liquid resulting, for example, from a container being placed abruptly on a hard surface. The use of a fixed vent requires a fixed direction or orientation (indicated on the spout) for pouring. Otherwise, the vent is occluded. The comments above on the drawbacks of snap-in caps also apply to the Merck cap.